RDMA/cma: Fix rdma_resolve_route() memory leak

stable inclusion
from stable-v4.19.198
commit 4893c938f2a140a74be91779e45e4a7fa111198f
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9R4ER
CVE: CVE-2021-47345

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4893c938f2a140a74be91779e45e4a7fa111198f

--------------------------------

[ Upstream commit 74f160ea ]

Fix a memory leak when "mda_resolve_route() is called more than once on
the same "rdma_cm_id".

This is possible if cma_query_handler() triggers the
RDMA_CM_EVENT_ROUTE_ERROR flow which puts the state machine back and
allows rdma_resolve_route() to be called again.

Link: https://lore.kernel.org/r/f6662b7b-bdb7-2706-1e12-47c61d3474b6@oracle.com


Signed-off-by: Gerd Rausch <gerd.rausch@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zhao Wenhui <zhaowenhui8@huawei.com>